False, get a group of 20 friends around, queue up for lfr and then go afk. You control the booting so you wont get booted. See how long it takes you to down the bosses. There is no gauranteed success. The determination buff had to be incorporated to give people a reason to stick with a group that wasn't going to one shot everything, that there was a chance to succeed. If you have the patience to stick around for 7 -20 wipes then they should just give you the gear as far as I am concerned because you certainly are stubborn.
Also the rewards are not gauranteed, you could far the same boss for months and never get the item you are looking for. There are no gaurantees. To call it a gaurantee is something you made up because it sounds good as a sound byte.
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Fasle, Effort is also investing time doing something even if that something is waiting for someone. If you don't want to wait for someone then you don't want to put up with the effort of waiting for them.
You can of course redefine the words all you want but ultimately you don't like doing grind because of what you have to do to complete it including the effort of investing the time into them.
And LFR rewards are all luck as well, in fact you will have better luck at burdens than LFR bosses because anything on the island can drop burdens and Bosses only have a random chance to drop a few random pieces once a week + coin. You could get 15 of the same ring in a row and never get the tier chest you are looking for. Every frog has a chance of dropping burdens, every 'rare' and you can kill them 24/7.